1. Field of Invention
The present invention relates to the field of clubfoot therapy. More specifically, the invention relates to methods of therapy for clubfoot when a relapse has occurred.
2. Description of Related Art
Clubfoot, though predominantly a condition that occurs in isolation (idiopathic clubfoot), is also well-recognized in a variety of pre-existing conditions. Throughout most of the 20th century the mainstay of treatment of clubfoot has been surgical correction involving a variety of techniques (Carroll N C, McMurtry R, Leete S F. The pathoanatomy of congenital clubfoot. Orthop Clin North Am. 1978; 9:225-232; Carroll N C. Surgical technique for talipes equinovarus. Oper Tech Orthop. 1993; 3:115-120; Crawford A H, Marxen J L, Osterfeld D L. The Cincinnati incision; a comprehensive approach for surgical procedures of the foot and ankle in childhood. J Bone Joint Surg [Am]. 1982; 64:1355-1358; McKay D W. New concept of and approach to clubfoot treatment: section II. Correction of the clubfoot. J Pediatr Orthop. 1983; 3:10-21; Turco V J. Surgical correction of the resistant clubfoot: one-stage posteromedial release with internal fixation. A preliminary report. J Bone Joint Surg [Am]. 1971; 53:477-497). “Good” to “excellent” initial results have been reported in the range of 52% to 91% for these surgical methods (Herzenberg J E, Radler C R, Bor N. Ponseti versus traditional methods of casting for idiopathic clubfeet. J Pediatr Orthop. 2002; 22:517-521; Roye D P, Roye B D. Idiopathic congenital talipes equinovarus. J Am Acad Orthop Surg. 2002; 10:239-248). However, surgical interventions have associated reported complications in 11% to 50% of cases (Applington J P, Riddle C D. Avascular necrosis of the body of the talus after combined medial and lateral release of congenital clubfoot. South Med J. 1976; 69:1037-1038; Atar D, Lehman W B, Grant A D. Complications in clubfoot surgery. Orthop Rev. 1991; 20:233-239; Crawford A H, Gupta A K. Clubfoot controversies: complications and causes for failure. MOS Instr Course Lect. 1996; 45:339-346; Miller J H, Bernstein S M. The roentogenographic appearance of the corrected clubfoot. Foot Ankle. 1986; 6:177-183; Schlafly B, Butler J E, Sift S J. The appearance of the tarsal navicular after posteromedial release for clubfoot. Foot Ankle. 1985; 5:222-237). Often, complications are related to the Achilles tendon that may result in calcaneal deformity, from over-lengthening of the tendon or equinus from insufficient posterior release with or without under-lengthening of the Achilles tendon (Crawford A H, Gupta A K. Clubfoot controversies: complications and causes for failure. AAOS Instr Course Lect. 1996; 45:339-346). Postoperative gait analysis has shown abnormalities in ankle rocker formation and timing (Alkjaer T, Pedersen E N, Simonsen E B. Evaluation of the walking pattern in clubfoot patients who received early intensive treatment. J Pediatr Orthop. 2000; 20:642-647; Asperheim M S, Moore N, Carroll N C, et al. Evaluation of residual clubfoot deformities using gait analysis. J Pediatr Orthop B. 1995; 4:49-54; Hee H T, Lee E H, Lee G S. Gait and pedographic patterns of surgically treated clubfeet. J Foot Ankle Surg. 2001; 40:287-294; Karol L A, Concha M C, Johnston C E 2d. Gait analysis and muscle strength in children with surgically treated clubfeet. J Pediatr Orthop. 1997; 6:790-795; Karol L A, Mayberry S, O'Brien O, et al. Gait in patients with clubfeet: a comparison of physical therapy versus surgical release. Pediatric Orthopaedic Society of North America 2003 Annual Meeting, Amelia Island, Fla., May 2-4, 2003; Kuo K N, Hennigan S P, Hastings M E. Long term results of clubfoot release, outcome study and gait analysis. Pediatric Orthopaedic Society of North America 2003 Annual Meeting, Amelia Island, Fla., May 2-4, 2003; Otis J C, Bohne W H. Gait analysis in surgically treated clubfoot. J Pediatr Orthop. 1986; 6:162-164; Widhe T, Berggren I. Gait analysis and dynamic foot pressure in the assessment of the treated clubfoot. Foot Ankle Int. 1994; 15:186-190) and kinetic studies have revealed a significant decrease in power generation, with an average gastrosoleus muscle complex strength reduction of 27% after one Achilles tendon lengthening (Karol L A, Concha M C, Johnston C E 2d. Gait analysis and muscle strength in children with surgically treated clubfeet. J Pediatr Orthop. 1997; 6:790-795; Karol L A, Mayberry S, O'Brien O, et al. Gait in patients with clubfeet: a comparison of physical therapy versus surgical release. Pediatric Orthopaedic Society of North America 2003 Annual Meeting, Amelia Island, Fla., May 2-4, 2003; Kuo K N, Hennigan S P, Hastings M E. Long term results of clubfoot release, outcome study and gait analysis. Pediatric Orthopaedic Society of North America 2003 Annual Meeting, Amelia Island, Fla., May 2-4, 2003; Widhe T, Berggren I. Gait analysis and dynamic foot pressure in the assessment of the treated clubfoot. Foot Ankle Int. 1994; 15:186-190).
Ponseti published a protocol of serial manipulations and castings in 1980, reporting, at that time, that traditional surgery could be avoided in 89% of cases (Laaveg S J, Ponseti IV. Long-term results of treatment of congenital clubfoot. J Bone Joint Surg [Am]. 1980; 62:23-31) and, more recently, excellent functional and clinical outcomes in 78% of patients at 30-year follow-up (Cooper D M, Dietz F R. Treatment of idiopathic clubfeet: a thirty-year follow-up note. J Bone Joint Surg [Am]. 1995; 77:1477-1489). Unresolved hindfoot equinus, occurring in 70% to 90% of cases, was treated with percutaneous Achilles tenotomy. Other investigators have reported their experiences using the method described by Ponseti, quoting similarly favorable outcomes, albeit over a shorter follow-up (<3 years). Similarly, the physical therapy method also requires a significant rate of Achilles tenotomy (Bensahel H, Guillaume A, Desgrippes Y. Results of physical therapy for idiopathic clubfoot: a long-term follow-up. J Pediatr Orthop. 1990; 10:189-192). Bensahel et al reported a 26% surgical rate, which includes Achilles tenotomy (Bensahel H, Guillaume A, Desgrippes Y. Results of physical therapy for idiopathic clubfoot: a long-term follow-up. J Pediatr Orthop. 1990; 10:189-192) and Richards and Wilson (Richards B S, Wilson H. Non-operative clubfoot treatment using physical therapy. International Society of Orthopaedic Surgery and Traumatology 3rd International Clubfoot Congress, San Diego, Calif., August 2002) reported a 47% overall tenotomy rate.
Once correction of the clubfoot is achieved by the chosen method, maintenance is required. Maintenance involves ‘boots and bars’ or various orthoses, and has the prerequisite of correction, regardless of the methods and therapy involved in correction (surgical, non-surgical, pharmaceutical or a combination of these). A clubfoot that was corrected and goes on to redevelop features of a clubfoot is considered a relapse or recurrence of clubfoot. Recurrence is observed in about 30% of cases, with the highest incidence between the ages of 2 and 5.
A method of therapy for recurring or relapsing clubfoot that permits restoration of the normal foot position without requiring surgical intervention is desirable and needed. Novel pharmaceutical compositions comprising botulinum toxin or toxins are derived from the bacterium Clostridium botulinum and cause reversible muscle denervation by blocking the release of acetylcholine at the neuromuscular junction, leading to muscle relaxation. Botulinum toxin, specifically botulinum toxin A, is currently used in the treatment of cerebral palsy, poststroke spasticity, and other instances of inappropriate muscle contraction.
Reiter (Reiter, F, Danni, M., Lagalla, G., Ceravolo, G., Provinciali, L. 1998. Low dose botulinum toxin eith ankle taping for the treatment of spastic equinovarus foot after stroke. Arch Phys Med Rehabil 79:532-535) teaches use of BTX-A in combination with taping methods for treatment of spasticity following stroke. This treatment was administered to adult patients with previously normal foot function and was not directed to clubfoot treatment.
Delgado (Delgado et al. A preliminary report of the use of botulinum toxin type A in infants with clubfoot: four case studies. Journal of Pediatric Orthopedics. 2000; 20(4):533-8) reported application of a nonsurgical intervention for clubfoot therapy with the initial management involving physical therapy. A group of infant patients under the age of 1 year with clubfoot deformity were treated with BTX-A to resolve the abnormal foot posture. Several of these patients' conditions were dystonic in nature due to underlying disorders, and could not be considered ‘idiopathic’ in nature. Delgado's methods involved injection into both the gastrocnemius and the posterior tibial muscles, and dosages varied from 6-11 IU/kg. Delgado's methods used multiple muscle sites at multiple irregular intervals (on average three separate injection events) for all patients. In addition, 50% of the patients required additional surgery after 1 year of age. No discussion of relapse or therapeutic approaches to relapse was addressed.
Cummings (Cummings, R J and Shanks, D E. A prospective randomized double-blind study of the usefulness of botox as an adjunct to serial manipulation and casting for congenital clubfeet. Pediatric Orthopaedic Society of North America Annual Meeting. Ottawa, Canada May 12-15, 2005) presented a study suggesting that use of Botox™ in combination with the Ponseti methods was not a successful treatment for clubfoot.
There are a wide variety of approaches to therapy of spastic muscle disorders, particularly clubfoot in infants. Given the range of casting and manipulation methods, and the range in patient classification, dosages and compositions of botulinum toxin used, the method may have promise, however very specific diagnoses and treatment methodologies may be required. The conclusions of Cummings (Cummings, R J and Shanks, D E. A prospective randomized double-blind study of the usefulness of botox as an adjunct to serial manipulation and casting for congenital clubfeet. Pediatric Orthopaedic Society of North America Annual Meeting. Ottawa, Canada May 12-15, 2005) suggest that the details of the methods used, including the injected sites, matter significantly. Merely ‘mashing together’ various treatment regimens as may be suggested by some studies will not be successful in both primary treatment of idiopathic clubfoot and prevention of relapse.
In situations where the clubfoot deformity relapses, surgical correction is currently the standard of care in almost every case. Surgical correction carries with it additional complications and, if surgical methods can be avoided, scarring, tissue weakness and overcorrection are also avoided, and in severe cases, multiple correction attempts may be made. Surgical correction of clubfoot is limited—tenotomy is strongly recommended to not be performed more than twice as it causes causing structural weakness in the tendon having adverse effects on recovery and gait. Non-invasive methods are better accepted by parents and caregivers, and are less distressing on the patient.